US3884790A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for electrolytically etching
Assignee: Mitsubishi Electric Corp
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Filing: 1973-06-29
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Granted: 1975-05-20
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Expires: 1993-06-29
Abstract
Abstract An apparatus for electrolytically etching a workpiece comprises means for interrupting a power source quickly when an abnormal phenomenon occurs, and means for accurately detecting an abnormal current attenuation occuring between an electrode and a workpiece. In the apparatus for electrolytically etching a workpiece, a saturable reactor constant voltage automatic controlling system is employed for the electrolytic etching power source, and in order to decrease the size of an interrupting thyristor and to complete the interrupting of the working current; an interrupting diode is inserted between the saturable reactor, a stepdown transformer and a three phase full wave rectification, and the interrupting thyristor is connected to the output and is turned on by an abnormal phenomenon detecting signal so that the feed to the workpiece and the electrode is stopped by a short circuit of the three phase alternating current between the saturable reactor and the stepdown transformer. The abnormal phenomenon occuring between the electrode and the workpiece in the electrolytic etching, is detected by employing a sample and hold circuit, an operational amplifier and a logic circuit to prevent damage to the electrode and the workpiece. Further, an apparatus for electrolytically etching a workpiece wherein an abnormal current attenuation is detected with high accuracy is provided so that the ripple component of the working power source due to a spark or voltage change component caused by electrical noise and spark, is detected with high accuracy.
Inventors
- 👤 Kazuhiko Kobayashi
- 👤 Tamio Takawashi
- 👤 Shinji Arai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:11
CPC Classifications
B; B23; B23H; B23H3/00; B23H3/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
229 words
Apparatus for electrolytically etching a workpiece which comprises: a three phase saturable reactor having an input and an output, three phase alternating current transformer means having primary windings and second windings, rectifier means for rectifying three phase alternating current having three inputs and first and second outputs, an electrode, an abnormal phenomenon detector, means connecting the input of said three phase alternating current saturable reactor to a three phase alternating current power source, means connecting the output of said three phase alternating current saturable reactor to the primary windings of said three phase alternating current transformer means, means connecting the secondary windings of said three phase alternating current transformer means to the three inputs of said rectifier means, means connecting the first output of said rectifier means to said electrode, means for connecting the second output of said rectifier means to said workpiece, means connecting said abnormal phenomenon detector between said electrode and said workpiece; an interrupting thyristor, interrupting diode means, means connecting said interrupting diode in parallel with the primary windings of said three phase alternating current transformer means, means connecting said interrupting thyristor to the direct current output of said interrupting diode means, means connecting said abnormal phenomenon detector to said interrupting thyristor to short circuit the primary windings of said three phase alternating current transformer means in response to the detection of an abnormal phenomenon signal.
Claim 2
Dependent Claim
229 words
Apparatus for electrolytically etching a workpiece which comprises: a three phase saturable reactor having an input and an output, three phase alternating current transformer means having primary windings and second windings, rectifier means for rectifying three phase alternating current having three inputs and first and second outputs, an electrode, an abnormal phenomenon detector, means connecting the input of said three phase alternating current saturable reactor to a three phase alternating current power source, means connecting the output of said three phase alternating current saturable reactor to the primary windings of said three phase alternating current transformer means, means connecting the secondary windings of said three phase alternating current transformer means to the three inputs of said rectifier means, means connecting the first output of said rectifier means to said electrode, means for connecting the second output of said rectifier means to said workpiece, means connecting said abnormal phenomenon detector between said electrode and said workpiece; an interrupting thyristor, interrupting diode means, means connecting said interrupting diode in parallel with the primary windings of said three phase alternating current transformer means, means connecting said interrupting thyristor to the direct current output of said interrupting diode means, means connecting said abnormal phenomenon detector to said interrupting thyristor to short circuit the primary windings of said three phase alternating current transformer means in response to the detection of an abnormal phenomenon signal.
Claim 3
Dependent Claim
30 words
An apparatus according to claim 1, wherein a series connection of a thyristor and a condenser is coupled to said electrode for interrupting the working current delivered to said workpiece.
Claim 4
Dependent Claim
45 words
An apparatus according to claim 1, wherein the abnormal phenomenon detector measures the working current for a small time increment by using a sample and hold circuit and an operational amplifier so as to detect an abnormal current attenuation by an abnormal phenomenon detecting circuit.
Claim 5
Dependent Claim
54 words
An apparatus according to claim 1, wherein the abnormal phenomenon detector measures the working voltage and the working current for a small time increment by using a sample and hold circuit and an operational amplifier so as to detect a spark caused between the electrode and the workpiece by an abnormal phenomenon detecting circuit.
Claim 6
Dependent Claim
138 words
An apparatus according to claim 1, wherein the abnormal phenomenon detector includes: a working voltage sample and hold circuit for sampling and holding the working voltage; a working current sample and hold circuit for sampling and holding the working current; a reference pulse generator for feeding a sample and hold reference pulse to both of the sample and hold circuits; a subtracting circuit for obtaining a differential between sampled working voltages from the sample and hold voltage; a subtracting circuit for obtaining a differential voltage of a working current waveform from a sample and hold voltage of the waveform; a level comparison circuit for comparing both of the differential voltage and each predetermined reference voltage; and a logic circuit for generating spark detecting signal by detecting a spark component from the signal detected in the level comparison circuit.
Claim 7
Dependent Claim
105 words
An apparatus according to claim 1, wherein the abnormal phenomenon detector includes: a sample and hold circuit for sampling and holding the working current; a reference pulse generator for feeding a sample and hold reference pulse to said circuit; a subtracting circuit for obtaining a differential voltage of the working current wave form from a sample and hold voltage of the working current waveform; a level comparison circuit for comparing said differential voltage and the predetermined reference voltage; and a logic circuit for generating an abnormal current attenuation signal by detecting an abnormal current attenuation component from the signal detected by the level comparison circuit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |